avian respiration

Question 1

list structures in avian anatomy involved in respiration

Answer 1

• nasal cavity (conchae, sinus, choana)
• larynx
• trachea
• syrinx
• lungs (bronchi, gas exchange tissue)
• air sacs

Question 2

label the concha of the avian nasal cavity

Answer 2

Question 3

what is the arrow pointing to

Answer 3

infraorbital sinus

Question 4

what is this structure and what does it do? why is it clincally relevant

Answer 4

connects trachea to sinuses
where you would want to swab for respiratory infections in birds

Question 5

what is this structure and why is it clincally significant

Answer 5

glottis. very easy to see and therefore intubate

Question 6

how is the avian trachea shaped and what advantage does this structure give the bird

Answer 6

the cartilage rings of a bird’s trachea are completely closed and interlapped (rather than C shaped rings in mammals). this makes the avian trachea very rigid to prevent distension and collapse
however - must be careful in terms of intubation DO NOT use ET tube with inflatable cuff in birds

trachea is also very long - makes it easy for infections to occur here

Question 6

what is the purpose of the syrinx in birds

Answer 6

Where they produce sound located at bifurcation of trachea

Question 7

describe the structure of avian lungs

Answer 7

branching
- have primary bronchus
- 4 sets of secondary bronchi
- parabronchi (site of gas exchange)

Question 8

what are air sacs and how do they aid avian respiration

Answer 8

air sacs are thin membranned tissue that are empty inside and filled with air. they help to make the bird lighter for flight and act as reservoirs of air
- poorly vascularised
- have 9 air sacs
- connected to pneumatic bones (bones filled with air to make brd lighter)
- evaporate heat loss
- help produce sound

however also good place for bacteria to grow and can form granulomas

Question 9

describe how air flows through the URT system and into the lungs and airsacs

Answer 9

birds dont have diaphragm so rely on movement of thorax during inspiration and expiration to pull air in and push it out (CR: dont squeeze birds as will die)
air inflow: sternum moves forward and down, ribs move cranially, lowering the pressure and air sacs expand. air rishes into trachea, then primary bronchi to lungs and caudal/cranial air sacs
air outflow: sternum moves back up, ribs move caudally, decreasing volume and forcing air out of air sacs
-caudal sacs empty into lungs, lungs and cranial sacs empty into trachea and out of body

Question 10

describe how gas exchange occurs in birds

Answer 10

• cross current blood flow
• one way airflow
• 10 times surface of exchange
• continuous exchange

allows for optimized system

Question 11

list the pneumatic bones in birds and how are they clinically relevant

Answer 11

reduce weight to make flying easier
- skull
- humerus
- clavicle
- keel
- pelvic girdle
- vertebrae

CR: air sacs are connected to pneumatic bones therefore must take care with placing intraosseous catheters as can cause aspiration of any fluids administered through them